


Caring for a Young Alpha

by castielsstarr



Category: Supernatural
Genre: Age Swap, Alpha Dean, Alpha/Beta/Omega Dynamics, Blow Jobs, First Rut, Knotting, M/M, Multiple Orgasms, Omega Sam, Plot What Plot/Porn Without Plot, Riding
Language: English
Status: Completed
Published: 2016-03-16
Updated: 2016-03-16
Packaged: 2018-05-27 00:32:55
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 3,564
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6262144
Author URL: https://archiveofourown.org/users/castielsstarr/pseuds/castielsstarr
Summary: <blockquote class="userstuff">
              <p>
  <i>"For the last few years, they had been telling him what would happen if he presented as an omega and went into heat, but they hadn't thought to warn him of what a rut was like."</i>
</p><p> </p><p>Sam wants to help his younger brother through his first rut. Dean is 16.</p>
            </blockquote>





	Caring for a Young Alpha

A slight creaking woke Sam in the middle of the night, the sound coming from his little brother’s side of the room. Usually he wasn't quick to waken at a sound so small, but something was keeping him on edge. He wasn't able to put his finger on why, but both him and Dean had been fidgety most of the night. 

When Sam looked over, there was no denying what the mystery creaking was. The bed was rocking back and forth as Dean humped against the mattress in his sleep. His eyes were shut tight, but his mouth open with heavy breaths. A wide expanse of freckle-dusted skin showed as the sheet slipped around his hips, back exposed to the air. He usually kept it wrapped tight around his shoulders when he slept, but it had fallen to his lower back and was slipping lower still with each downward thrust.

“Dean,” Sam hissed, hoping that the boy would stir and stop rutting against the mattress, but he didn’t react. At the same moment that Dean growled low in his throat, Sam caught a wiff of the crushing, overpowering smell of alpha. 

Holy shit. 

His little brother wasn't supposed to be an alpha. Both Sam and their dad had thought that Dean was going to present omega or maybe beta, but they hadn't guessed this. He was too small to be an alpha. He didn't have the muscular build, the height, or the aggression that went along with it.

That scent was undeniable, though. Full-fledged alpha. It was musky and deep with hints of what he thought smelled like cinnamon. The reaction it caused was unlike any he’d had to any alpha he’d come across. Sam could feel the way that deliciousness was settling in his bones, wrapping around him, warming him, as he inhaled. He'd be a damned liar if he said his cock wasn't hardening beneath the sheet that covered him, too.

Dean groaned from the other bed, continuing to grind against it as the next coherent thought came to Sam's mind. If Dean just presented as an alpha, that meant this was his first rut. He wasn’t prepared for this. For the last few years, they had been telling him what would happen if he presented as an omega and went into heat, but they hadn't thought to warn him of what a rut was like. The next growl trailed off with a whine and he knew that Dean was going to need help.

Crawling out of his bed, he made it a couple steps before the next wave of Dean's scent hit him, stronger than before. It made him gasp and he could feel his body responding to it like a good omega, slick starting to leak onto his thighs. When he reached the other bed, he had to sit down on the edge and take a few breaths to steady himself. His own scent was now filling the room, too, and he knew that something was off about it. The combination of their scents shouldn’t smell that intoxicating. It was thick in the air and he wondered if he could taste it if he stuck his tongue out. He didn’t, though, and brought his attention back to his little brother.

The sheet had shifted far enough that it left the majority of one whole ass cheek exposed and his right thigh and leg, though Sam couldn’t see anything else. However, it was more than enough to let him know that the young alpha hadn't worn boxers to bed that night, either. The room had already been filled with summer heat and the room lacked an air conditioner, which was only going to make this worse for the teen. Whether in heat or rut, it was normal for the body temperature to spike. The heat was annoying before and it was probably edging on unbearable now.

Now that Sam was next to him, he could see that Dean wasn’t humping just the mattress. He had shoved a pillow between his legs at some point during the night and was working himself against it. Even in the dark, he could see the way it was covered in dampness. Sixteen year olds leaked like crazy when they were horny anyway, but a fresh alpha was something else. Brand new ones leaked from their cocks almost as much as an omega’s hole. Dean whimpered and he knew he had to be starting to chafe by this point. Slick fabric wasn’t going to be enough.

Freckled skin was hot and sweaty when he touched Dean's shoulder. God, even Sam's fever had never gotten that high, even during his first heat. Should he get him a cool compress instead? He knew it wasn’t going to help much. The quickest way to get an alpha’s fever down was to get his knot inside of an omega. This wasn’t even close to the first time Sam had thought about it—he just had to make sure that Dean was on board. The boy didn’t respond to the first few nudges, but after a hard jostle to his shoulder, the alpha woke up.

Dean's eyes flew open and he gasped, startled both by the person waking him up abruptly and the final jerk of his hips against the pillow before he realized what he was doing. He was panting hard as he met the omega’s eyes, trying to get his body back under his control.

"Sam? Why are you—what's happening?" He growled low and loud, the sound rippling through Sam's spine. He looked surprised that the noise came out of him, but to Sam it felt like it was tugging at those small dimples above his ass, making him want to present for his little brother. He wanted so badly to be claimed, even though it was considered almost shameful to be an older omega taken by a younger alpha.

He needed to focus on Dean right now, not his own urges. "Remember how, uh, Dad and I told you what would happen if you presented as an omega?"

"Yeah, b-but—" He grunted under his breath, trying to keep his focus on Sam. "—this isn't like what you told me. Fuck, it hurts!”

His hand slid from shoulder down to rub small circles at the small of Dean’s back, the motion making the boy shiver violently. Any touch was going to drive the alpha in him crazy right now, but Sam couldn't stand the idea of taking his hand off his heated skin. His omega wanted more, but for right now it was placated with touching. "You're right, this isn’t the same. This is a rut.”

“A what?” Dean looked confused.

“Rut. It's the equivalent of a heat, but for alphas. We thought there was little chance of you presenting as an alpha since the only other one in our family was Mom’s dad, so we didn’t talk to you about this.”

Frantic, panicked looks passed over Dean's face and he was shaking, gripping at the sheets. They were balled in his fists as he tried to keep still, tried not to shamelessly grind against the pillow beneath him. There was nothing there to be ashamed of, but Dean didn't know that. It was Sam’s fault that he was so scared right now and that wasn’t acceptable.

"Hey, everything's ok. Just breathe."

"Can't.” Dean’s breaths were coming short and fast, almost hitting the level of hyperventilation. “It's so hot in here." His concentration broke just enough and his hips bucked forward, making him moan loudly as his dick rubbed against the pillow. Dean tried to bite back the rest of the moan, clenching his jaw shut tight, but it failed to muffle anything. "I'm s-sorry."

"Don't be.” The sound traveled through Sam, tingling along his hardened cock and tight balls before rushing back to his hole. Sam could feel a small gush of slick soak into the bedding beneath him and it was all he could do not to moan, too. It was the same as when he had come home early from work one day and accidently caught sight of Dean masturbating, jacking his cock with one finger pushing into his ass. He hadn’t wanted Dean to be surprised or frightened by the intense need he was going to have when he presented omega, so he had said that fingers would help ease him into it. “We need to take care of you or it's going to get worse."

Dean groaned, and it wasn't in pleasure. "It can get worse than this?” He shifted a little, and it was easy to tell that he was pulling his cock away from any contact with the way his ass canted up. It already feels like I'm on fire and drowning at the same time."

At least part of that was an easy fix. "Here, let's get the sheet off you."

"N-no!" He grabbed at the edge of it, pulling it higher up his back. "I'm, uh, it was hot and I didn't wear anyth—"

"Dean, I know. Your ass has been hanging out for a while now." 

The heat of embarrassment would have visibly crept up his cheeks if they weren't already flushed red and he looked away. Without rubbing himself against anything, a small moan fell from his open lips. Sam could see his nostrils flaring as he scented the air, finally focusing enough to pick up on it. "Is that you? Why do you smell so good?"

Fuck, Dean could smell it, too. Sam had to take a calming breath and look away from the little alpha. He needed to keep collected right now, not give into the omega instinct that was telling him to put his ass in the air and beg for it. "That's your alpha being attracted to my omega. It finds something it likes and your brain tells you that it smells good. It's how mates find each other."

Luckily, the mate part didn’t stick in his mind, but Dean jumped to a whole different issue. "But you're my brother. How can I be attracted to my own brother?"

Sam didn't really have a good answer and "just 'cause" wasn't going to suffice. Luckily, he didn't have to come up with anything right then because Dean whined a little, a sound still so rare even on new alphas. "My dick hurts so bad, Sam."

He turned back to Dean and the words tumbled past his lips before he could even think about stopping them. "If you roll over, I can help take care of you. I can make the hurting stop." More slick was seeping out of him at just the thought of getting fucked open on his little brother’s cock. It didn’t matter how big or thick the alpha was, Sam just needed. 

Dean was about to protest—could see it in the way his jaw set as he opened his mouth to speak—but Sam interrupted him before he could. "There aren't any 24-hour pharmacies around here, so we couldn't get you a toy until morning. That’s at least six hours and the pain is only going to keep getting worse. I don’t like seeing you hurting, alpha." He couldn't fight what his instincts were telling him anymore and he ducked his head to nuzzle into the hair behind his little brother's ear.

Something must have clicked in Dean with the omega's act of submission because he rolled off of the pillow and tossed it away, centering himself in the middle of the bed. With the way his hips rolled underneath the sheet pulled taut over his groin, it was easy to see how long and hard he was. His cock was large and Sam whimpered at the sight of it. Dean still didn’t say anything, but he was biting into his lower lip in a way that couldn’t be anything less than seductive. 

"I promise I'll make you feel better," Sam whispered as a decent portion of his control broke and he leaned down to mouth sloppy kisses against the skin of Dean's stomach. The movement could have ruined everything, but the alpha's panting grew louder as he moved lower over sweat-salty skin, closer to what Dean needed.

He replied as Sam dipped the tip of his tongue into his belly button, then kissed the trail of fine hair below it. "I never, _ah_ , thought my first time was going to be with my big brother."

Relief flooded him to hear the alpha consent to it. He was getting too worked up and he didn’t want to stop—his own dick swinging rock hard between his legs and hole fluttering around nothing, wanting to be filled. He would have stopped if Dean didn’t want this, but it would have been hard to pull himself away.

The white cotton bedding was still covering Dean’s cock and Sam kneaded him through the material causing Dean to cry out and thrust against his hand. The fabric was already wet where he had soaked through that, too. 

"Have you gotten a blowjob before? Maybe from any of the girls at school?" His hand had stilled, but Dean kept rubbing against it passively, almost like he didn't notice he was doing it.

"Yeah, of course,” he said, panting. “A couple of girls."

"Good, then you’ll have something to compare it to.” Sam removed his hand and pulled the sheet down, watching as Dean's cock sprang free, bouncing a few times against his stomach. There was a small ring near the root where his knot was starting to show, waiting to swell and fill more. Fuck, he needed to make it pop. “This is going to feel better than before." 

Sam took the head and most of the shaft into his mouth without any more preamble and sucked, causing Dean's back to arch off the bed. He kept with the motion, never moving low enough to take that swelling ring into his mouth. It was bigger than before, starting to fill with come. His cock was enormous, but it wasn’t until it was inside Sam’s mouth, stretching his lips wide, that he realized just how big. A sixteen year old shouldn’t have a cock as thick around as a beer bottle, but Dean’s was certainly close. Sam realized he desperately wanted it splitting open more than just his mouth.

He pulled off and gave a few appreciative licks to the head, the flat of his tongue passing over Dean’s slit, causing a large bead of precome to burst from it. Sam paused for just a second to ask, "How does it feel?" before his mouth enveloped Dean again.

"Fuck, S-Sam. It's— _aaahh_!" He tossed his head back as his older brother took him deeper, his lips pushing down over the knot. His head bobbed slightly, keeping lips sealed tight as they shifted back and forth over his knot. It was starting to expand, forcing his mouth wider, skin cracking at the sides. It was one of the few pains that still felt so deliriously good and Sam moaned in tandem with Dean, the vibrations thrumming into his knot, making him scream. Luckily, the motel was trashy enough that no one was going to come knocking on their door telling them to shut up.

It took a few slow and shallow sucks to ease Dean back down from his high before Sam was willing to pull off. He leaned up over his younger brother, their eyes meeting and holding the other’s rapt attention. Sam leaned in close, letting the bare traces of his words be felt over Dean’s face in puffs of air. "You're going to have such a huge knot when you finally come. I can't wait to have it filling me up."

Dean swallowed thick, his throat clicking with the lack of moisture. "Won't it, uh, hurt you?" He was having a hard time catching his breath and the shivering started.

Sam shook his head and moved, legs landing on either side, so that he was straddling Dean's waist. "Omegas are designed to take knots, remember? I've got this to help me." Two fingers reached behind to swipe at his hole, collecting the slickness that was soaking him now. He brought those fingers back to show Dean how wet and ready he was, but he didn't anticipate his brother grabbing his hand and sucking those fingers into his mouth.

If Sam didn't know better, he would've guessed that Dean just came from the sound that he made at getting to taste his older brother. He suckled and thoroughly licked each digit until the slick was gone, then let them slide from his mouth. The growl was back in his voice and his hands moved to grip tightly at Sam’s hips, trying to force him down onto his cock. "God, you taste so good. I want to shove my tongue so deep in your ass and lick until you're clean."

Sam laughed and reached behind himself to gather just a little more. "Maybe another time, alpha," he murmured and slid the fingers back into Dean's mouth. "We need to get that knot to pop soon or you're going to hurt even worse." While Dean's eyes were closed, enjoying the taste of slick, Sam let himself be pushed onto the head of his cock, sinking halfway down. 

Dean's eyes clamped tighter shut and Sam pushed the rest of the way down with a long moan until he was fully seated. He knew it was going to feel good, but this was more than he’d bargained for. The boy below him bucked his hips, trying to get him to move, but Sam stayed still, leaning over to lightly brush their lips together.

Hesitation, unsurety, was what he expected, but the kiss was met with fervor. A hand laced into his hair, holding him in place as Dean's tongue snaked into his mouth. Their breath was hot together as Dean licked over every inch of his mouth, sucking in the taste of his omega. Sam didn't let their tongues play against each other for much longer before he pulled back, resting their foreheads together.

"I know your instinct is to fuck and take, but I want you to try and go slow, ok?" Sam didn't wait for Dean's answer before he started to roll his hips, causing the knot to slip in and out of his relaxed hole. Nails were digging into his back as he kept up the constant, maddeningly-slow drag. Dean was reduced to growls and moans, only stopping to place rough kisses to Sam's open, panting mouth. He was so thick inside of him that every slow thrust back onto the alpha's cock was rubbing against his prostate, causing more slick to fill him.

"You feel so good inside me, alpha. I can feel your knot swelling." His voice had gone breathy and his rhythm started to falter. Neither of them could hold out for much longer, the slow pace making the sensations stronger than they were. "You're so close already. Next time, I'll let you fuck me rough, alpha, promise." He was going to warn Dean, but his orgasm hit him unexpectedly, his hole clamping down tight around his alpha's knot, come striping both of their stomachs white. 

Even though he couldn't hear it over his own whines and whimpers, he could feel Dean's breath hot on his cheek as he moaned. Dean's knot was expanding quickly until it was locked inside of him, huge and likely aching. He was going to make him feel so much better, though. "Sam, _shit_ I'm going to— _nnng_ , oh god—fuck, fuck!" He ground his knot inside Sam and the omega's needy hole milked his cock until he came hard.

Sam could feel come splashing hot inside of him, filling him up so good, and he couldn't help pulling back and watching his alpha little brother's face as he had his first knotted orgasm. His eyes were hooded, mouth open wide, face twisted in intense pleasure. He kept grinding his hips up into his omega and as he was starting to settle, Sam purposefully clenched around his knot, setting off his second orgasm and letting more come seep into his drenched hole.

Dean was screaming and clinging to him as Sam milked three, four, and five out of him. The look on his face—eyes wide and lips bitten red—revealed that he hadn’t known alpha’s could come more than once. Sam had to commit that face to memory because it was one of the hottest things he had ever seen before. After Dean came down from the fifth one, they both collapsed. He managed to roll them onto their sides, so that his larger frame wasn't crushing the small alpha. 

They were face to face, tied together for a while at least. He expected this part to be awkward; when the intensity of Dean's rut was wearing off and he might be questioning why he let this happen. However, he was pleased when Dean pulled him into his arms, bodies pressed as close as they could be at all points, and kissed him languidly. Sam could feel the smile on his brother's lips, and now confident that this was ok with him, returned the affection.

They still hadn't stopped kissing by the time Dean's knot went down.

**Author's Note:**

> Come hang out with me on Tumblr, I promise I don't bite:  
> SPN NSFW Multi-ship sideblog: [wingedwincest.tumblr.com](http://www.wingedwincest.tumblr.com)  
> Main blog: [castielsstarr.tumblr.com](http://www.castielsstarr.tumblr.com)


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